<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <div id="app">hello</div>

  <script>
    let app = document.getElementById('app')

    app.style.position = 'relative';
    
    app.style.width = '100px'
    app.style.height = '200px'
    app.style.left = '10px'
    app.style.top = '10px'

    console.log(app.offsetTop);
    console.log(app.offsetWidth);
    console.log(app.offsetHeight);
    console.log(app.offsetLeft);

    // app.style.cssText = 'width: 100px; height: 100px;left: 10px; top: 10px;'

  </script>
</body>
</html>